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    <h1 align="CENTER">Module mod_auth_digest</h1>

    <p>This module provides for user authentication using MD5
    Digest Authentication.</p>

    <p><a href="module-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="module-dict.html#SourceFile"
    rel="Help"><strong>Source File:</strong></a>
    mod_auth_digest.c<br />
     <a href="module-dict.html#ModuleIdentifier"
    rel="Help"><strong>Module Identifier:</strong></a>
    digest_auth_module<br />
     <a href="module-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later.</p>

    <h2>Summary</h2>

    <p>This is an updated version of <a
    href="mod_digest.html">mod_digest</a>. However, it has not been
    extensively tested and is therefore marked experimental. If you
    use this module, you must make sure to <em>not</em> use
    mod_digest (because they share some of the same configuration
    directives).</p>

    <p>Digest authentication is described in <a
    href="http://ftp.ics.uci.edu/pub/ietf/http/rfc2617.txt">RFC 
    2617.</p>
 
    <h2>Directives</h2>

    <ul>
      <li><a href="#authdigestfile">AuthDigestFile</a></li>

      <li><a
      href="#authdigestgroupfile">AuthDigestGroupFile</a></li>

      <li><a href="#authdigestqop">AuthDigestQop</a></li>

      <li><a
      href="#authdigestnoncelifetime">AuthDigestNonceLifetime</a></li>

      <li><a
      href="#authdigestnonceformat">AuthDigestNonceFormat</a></li>

      <li><a href="#authdigestnccheck">AuthDigestNcCheck</a></li>

      <li><a
      href="#authdigestalgorithm">AuthDigestAlgorithm</a></li>

      <li><a href="#authdigestdomain">AuthDigestDomain</a></li>
    </ul>

    <p>See also: <a href="core.html#require">Require</a> and <a
    href="core.html#satisfy">Satisfy</a>.</p>

    <h3><a id="usingdigest" name="usingdigest">Using Digest
    Authentication</a></h3>

    <p>Using MD5 Digest authentication is very simple. Simply set
    up authentication normally, using "AuthType Digest" and
    "AuthDigestFile" instead of the normal "AuthType Basic" and
    "AuthUserFile"; also, replace any "AuthGroupFile" with
    "AuthDigestGroupFile". Then add a "AuthDigestDomain" directive
    containing at least the root URI(s) for this protection space.
    Example:</p>
<pre>
  &lt;Location /private/&gt;
  AuthType Digest
  AuthName "private area"
  AuthDigestDomain /private/ http://mirror.my.dom/private2/
  AuthDigestFile /web/auth/.digest_pw
  Require valid-user
  &lt;/Location&gt;
</pre>

    <p><strong>Note:</strong> Digest authentication is more secure than
    Basic authentication, but only works with supporting browsers. As of
    September 2004, major browsers that support digest authentication
    include <a href="http://www.w3.org/Amaya/">Amaya</a>, <a
    href="http://konqueror.kde.org/">Konqueror</a>, <a
    href="http://www.microsoft.com/windows/ie/">MS Internet Explorer</a>
    for Mac OS X and Windows (although the Windows version fails when
    used with a query string -- see "<a href="#msie" >Working with MS
    Internet Explorer</a>" below for a workaround), <a
    href="http://www.mozilla.org">Mozilla</a>, <a
    href="http://channels.netscape.com/ns/browsers/download.jsp">
    Netscape</a> 7, <a href="http://www.opera.com/">Opera</a>, and <a
    href="http://www.apple.com/safari/">Safari</a>. <a
    href="http://lynx.isc.org/">lynx</a> does <strong>not</strong>
    support digest authentication. Since digest authentication is not as
    widely implemented as basic authentication, you should use it only
    in environments where all users will have supporting browsers.</p>
    <hr />

    <h2><a id="authdigestfile"
    name="authdigestfile">AuthDigestFile</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     

    <p>The AuthDigestFile directive sets the name of a textual file
    containing the list of users and encoded passwords for digest
    authentication. <em>File-path</em> is the absolute path to the
    user file.</p>

    <p>The digest file uses a special format. Files in this format
    can be created using the <a
    href="../programs/htdigest.html">htdigest</a> utility found in
    the support/ subdirectory of the Apache distribution.</p>
    <hr />

    <h2><a id="authdigestgroupfile"
    name="authdigestgroupfile">AuthDigestGroupFile</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestGroupFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p>The AuthDigestGroupFile directive sets the name of a textual
    file containing the list of groups and their members (user
    names). <em>File-path</em> is the absolute path to the group
    file.</p>

    <p>Each line of the group file contains a groupname followed by
    a colon, followed by the member usernames separated by spaces.
    Example:</p>

    <blockquote>
      <code>mygroup: bob joe anne</code>
    </blockquote>
    Note that searching large text files is <em>very</em>
    inefficient. 

    <p>Security: make sure that the AuthGroupFile is stored outside
    the document tree of the web-server; do <em>not</em> put it in
    the directory that it protects. Otherwise, clients will be able
    to download the AuthGroupFile.</p>
    <hr />

    <h2><a id="authdigestqop"
    name="authdigestqop">AuthDigestQop</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestQop
    none|auth|auth-int [auth|auth-int]<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a> <code>AuthDigestQop
    auth</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p>The AuthDigestQop directive determines the
    quality-of-protection to use. <em>auth</em> will only do
    authentication (username/password); <em>auth-int</em> is
    authentication plus integrity checking (an MD5 hash of the
    entity is also computed and checked); <em>none</em> will cause
    the module to use the old RFC-2069 digest algorithm (which does
    not include integrity checking). Both <em>auth</em> and
    <em>auth-int</em> may be specified, in which the case the
    browser will choose which of these to use. <em>none</em> should
    only be used if the browser for some reason does not like the
    challenge it receives otherwise.</p>

    <p><strong><em>auth-int</em> is not implemented
    yet</strong>.</p>
    <hr />

    <h2><a id="authdigestnoncelifetime"
    name="authdigestnoncelifetime">AuthDigestNonceLifetime</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestNonceLifetime
    <em>seconds</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AuthDigestNonceLifetime 300</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p>The AuthDigestNonceLifetime directive controls how long the
    server nonce is valid. When the client contacts the server
    using an expired nonce the server will send back a 401 with
    <code>stale=true</code>. If <em>seconds</em> is greater than 0
    then it specifies the amount of time for which the nonce is
    valid; this should probably never be set to less than 10
    seconds. If <em>seconds</em> is less than 0 then the nonce
    never expires. <!-- Not implemented yet
            If <EM>seconds</EM> is 0 then the nonce may be used exactly once
            by the client. Note that while one-time-nonces provide higher security
            against replay attacks, they also have significant performance
            implications, as the browser cannot pipeline or multiple connections
            for the requests. Because browsers cannot easily detect that
            one-time-nonces are being used, this may lead to browsers trying to
            pipeline requests and receiving 401 responses for all but the first
            request, requiring the browser to resend the requests. Note also that
            the protection against reply attacks only makes sense for dynamically
            generated content and things like POST requests; for static content
            the attacker may already have the complete response, so one-time-nonces
            do not make sense here.
            -->
    </p>
    <hr />

    <h2><a id="authdigestnonceformat"
    name="authdigestnonceformat">AuthDigestNonceFormat</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestNonceFormat
    <em>???</em><br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AuthDigestNonceFormat ???</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p><strong>Not implemented yet.</strong> <!--
            <P>The AuthDigestNonceFormat directive determines how the nonce is
            generated.
            -->
    </p>
    <hr />

    <h2><a id="authdigestnccheck"
    name="authdigestnccheck">AuthDigestNcCheck</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestNcCheck
    On|Off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AuthDigestNcCheck Off</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> server config<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> <em>Not
    applicable</em><br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p><strong>Not implemented yet.</strong> <!--
            <P>The AuthDigestNcCheck directive enables or disables the checking of the
            nonce-count sent by the server.

            <P>While recommended from a security standpoint, turning this directive
            On has one important performance implication. To check the nonce-count
            *all* requests (which have an Authorization header, irrespective of
            whether they require digest authentication) must be serialized through
            a critical section. If the server is handling a large number of
            requests which contain the Authorization header then this may noticeably
            impact performance.
            -->
    </p>
    <hr />

    <h2><a id="authdigestalgorithm"
    name="authdigestalgorithm">AuthDigestAlgorithm</a>
    directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestAlgorithm
    MD5|MD5-sess<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AuthDigestAlgorithm MD5</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p>The AuthDigestAlgorithm directive selects the algorithm used
    to calculate the challenge and response hashes.</p>

    <p><strong><em>MD5-sess</em> is not correctly implemented
    yet</strong>. <!--
            <P>To use <EM>MD5-sess</EM> you must first code up the
            <VAR>get_userpw_hash()</VAR> function in <VAR>mod_auth_digest.c</VAR> .
            -->
    </p>
    <hr />

    <h2><a id="authdigestdomain"
    name="authdigestdomain">AuthDigestDomain</a> directive</h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDigestDomain
    <em>URI</em> [<em>URI</em>] ...<br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Experimental<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_digest<br />
     <a href="directive-dict.html#Compatibility"
    rel="Help"><strong>Compatibility:</strong></a> Available in
    Apache 1.3.8 and later 

    <p>The AuthDigestDomain directive allows you to specify one or
    more URIs which are in the same protection space (i.e. use the
    same realm and username/password info). The specified URIs are
    prefixes, i.e. the client will assume that all URIs "below"
    these are also protected by the same username/password. The
    URIs may be either absolute URIs (i.e. inluding a scheme, host,
    port, etc) or relative URIs.</p>

    <p>This directive <em>should</em> always be specified and
    contain at least the (set of) root URI(s) for this space.
    Omitting to do so will cause the client to send the
    Authorization header for <em>every request</em> sent to this
    server. Apart from increasing the size of the request, it may
    also have a detrimental effect on performance if
    "AuthDigestNcCheck" is on.</p>

    <p>The URIs specified can also point to different servers, in
    which case clients (which understand this) will then share
    username/password info across multiple servers without
    prompting the user each time. 
    <!--#include virtual="footer.html" -->
    </p>
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